Side tensioning system for retaining screen media in a vibrating-type screening machine

ABSTRACT

The present invention relates to side tensioning assemblies for retaining screen media to the side plates of a vibrating-type screening machine. The side tensioning assembly includes a tensioning rail and at least one angle box mountable to a side plate. At least one bolt assembly provided for fastening the tensioning rail to the side plate and to angle box. Bolt assembly is provided with is a shoulder bolt that is secured to a terminal end of the bolt. The angle box includes an aperture sized to allow the bolt assembly passage therethrough, and a movable plate with a cutout. The cutout is sized larger than the bolt but smaller than a nut. The movable plate has a bolt-securing position and a bolt-releasing position to allow access to the aperture in the angle box such that the bolt assembly can be detached from the angle box without being disassembled.

FIELD OF THE INVENTION

The present invention relates generally to mechanical systems forholding in place screen media in a vibrating-type screening machine, andmore specifically, to side tensioning assemblies for retaining suchscreen media to the side plates of a vibrating-type screening machine.

BACKGROUND OF THE INVENTION

Vibrating-type screening machines typically have vibrating mechanismoperatively connected to deck frames which support screen media. In manysuch machines, the screen media is tightly held by side tensioning andsupported below by a suitable structure typically imparting a curvedshape to the screen media. This involves employing tensioning assembliesaffixed to side plates which stand tall of the deck frame. A typicalside tensioning assembly includes a tension rail fastened to the sideplate using fastening hardware. The tension is configured to engagetensioning hooks connected to side edges of the screen media. Whendeployed, the tension rail applies a tensile force on the tensioninghooks which operates to draw the screen media down toward the deck frameand outward toward the side plate.

In some tensioning assemblies, the direction of the tensile force can beadjusted using an angle box mounted to the outer surface of the sideplate. The angle box has a wedge-like structure which has an oblongopening formed therein that is configured to communicate with anaperture defined in the side plate. The oblong opening in the wedge-likestructure and the aperture defined in the side plate are aligned toreceive therethrough a bolt having a particular angled orientation whichcorresponds to the desired direction in which the tensile force is to beapplied. The bolt is part of the fastening hardware that is used to tiethe tension rail to the side plate.

In a typical installation of such a tensioning assembly, the bolt isfirst fitted through an aperture formed in the tension rail. Theremaining portion of the bolt is inserted through the aperture definedin the side plate and extends through the oblong opening in the anglebox. The terminal end of the bolt protrudes from the angle box away fromthe side plate, where a washer and nut engage the bolt. In order tocreate the requisite tension to retain the screen media, the nut istightened against the washer which sits between the angle box and thenut.

Such tensioning assemblies tend to be effective in tightly retaining thescreen media between the side plates. However, concerns have beenexpressed regarding the number of loose parts in such tensioningassemblies. More specifically, in the tensioning assembly of the typedescribed above, the fastening hardware includes a bolt, a nut and awasher, and then there is also the tension rail. Some vibrating-typescreen machines can be quite large and have multiple deck frames stackedone over the other. Such machines tend to require many sections oftension rail and many tensioning assemblies, thereby furtherexacerbating the problem of having too many loose parts. Such parts taketime to assemble and can easily be dropped, mishandled or lost, therebyleading to increased downtime of the machine while the screen media isbeing replaced. As a result, a steady supply of replacement fasteninghardware must be kept on hand. This can be a serious disadvantage inapplications which require frequent replacement of the screen media dueto wear and tear or other reasons. All the more so, because such screenmedia maintenance or service activities typically require two workmen tocarry them out.

In light of the foregoing, it would be advantageous to have a tensioningassembly which can easily be deployed rapidly and with ease, and whichobviates the above-described drawbacks associated with known tensioningassemblies that employ angle boxes.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, there isprovided a side tensioning assembly for retaining screen media to a sideplate in a vibrating-type screening machine. The side plate has an innersurface and an outer surface. The side tensioning assembly includes atensioning rail mountable to the inner surface of the side plate andconnectable to a portion of the screen media; at least one angle boxmountable to the outer surface of the side plate; and at least one boltassembly for fastening the tensioning rail to the side plate and to theat least one angle box. The at least one bolt assembly includes a boltconnectable to the tensioning rail, the side plate and the at least oneof angle box, a nut threadably engaged with the bolt for retaining thebolt to the at least one the angle box, and a shoulder bolt secured to aterminal end of the bolt. The shoulder bolt is sized to prevent the nutfrom becoming physically separated from the bolt. The at least one anglebox includes an aperture defined therein which is sized to allow thebolt assembly unobstructed passage therethrough. The at least one anglebox also has a movable plate with a cutout formed therein. The cutout issized larger than the bolt but smaller than the nut. The movable plateis movable between a bolt-securing position and a bolt-releasingposition. In the bolt-securing position, the movable plate partiallyoccludes the aperture in the angle box with the cutout aligned with theaperture in the angle box such that when the bolt is tightly fastened tothe angle box with the nut, the tensioning rail is drawn tightly againstthe inner surface of the side rail thereby applying a tensile force tothe portion of the screen media. In the bolt-releasing position, themovable plate is positioned so as to provide unobstructed access to theaperture in the angle box such that the bolt assembly can be detachedfrom the angle box without requiring disassembly of the bolt assembly.

In another feature, the bolt is a carriage bolt. In a further feature,the nut is a flange nut. In yet another feature, the nut is a first nut,and the side tensioning assembly further includes a second nut forsecuring the bolt to the tensioning rail. The second nut is a half nut.

In an additional feature, the aperture in the angle box is circular.Alternatively, the aperture in the angle box has a shape selected fromthe group consisting of: (a) circle; (b) a square; (c) a rectangle; (d)an oval; and (e) an oblong.

In another feature, the movement of the movable plate relative to theangle box is selected from the group consisting of: (a) translation; (b)rotation; and (c) a combination of sliding and rotation.

In alternative feature, the movable plate is slidable relative to theangle box in a motion selected from the group consisting of: (a)side-to-side motion; (b) up and down motion and (c) motion along adiagonal direction. In another alternative feature, the movable plate ishingedly connected to the angle box. In a further feature, the movableplate is pivotally connected to the angle box. Optionally, the movableplate may be tethered to the angle box.

In a further feature, the angle box includes first and second pinsattached thereto. The movable plate has defined therein first andsecond, spaced apart slots. Each slot is configured to receivetherethrough a respective one of the first and second pins.

The slots serve as a track to guide sliding movement of the movableplate relative to the angle box. In one feature, the slots have anorientation selected from the group consisting of: (a) a verticalorientation; (b) a horizontal orientation; and (c) a diagonalorientation.

In still another feature, the movable plate is generally planar and thesliding movement of the movable plate is confined along the plane of themovable plate.

In yet another feature, the angle box includes a base portion and awedge-shaped structure carried on the base portion. The wedge-shapedstructure has an wall oriented on an angle through which the aperture inthe angle box is formed. The movement of the movable plate between thebolt-releasing position and the bolt-securing position occurs generallyparallel to the angled wall of the wedge-shaped structure.

In one feature, the angle box includes a base portion and a wedge-shapedstructure carried on the base portion. The first second pins areattached to one of the base portion and the wedge-shaped structure.

In another alternative feature, the movable plate includes a first mainplanar portion and a second portion angled away from the first mainportion. The first and second slots extend through both the first andsecond portions of the movable plate. The angle box includes a baseportion and a wedge-shaped structure carried on the base portion. Thewedge-shaped structure has an wall oriented on an angle through whichthe aperture in the angle box is formed. When the movable plate is movedto its bolt-securing position, the first main planar portion liesgenerally parallel to the angled wall of the wedge-shaped structure.When the movable plate is moved to its bolt-releasing position, thefirst main planar portion has a skewed orientation relative to theangled wall of the wedge-shaped structure.

In a further feature, the angle box includes a pin attached thereto. Themovable plate has defined therein a slot configured to receivetherethrough the pin. The slot serves as a track to guide the slidingand the swiveling movement of the movable plate relative to the anglebox.

In another broad aspect of the present invention, there is provided aside tensioning system for retaining screen media between opposed firstand second side plates in a vibrating-type screening machine. Each sideplate has an inner surface and an outer surface. The side tensioningsystem includes a first tensioning assembly operatively connectable tothe first side plate. The first tensioning assembly includes a firsttensioning rail mountable to the inner surface of the first side plateand connectable to a first portion of the screen media, at least oneangle box mountable to the outer surface of the first side plate, and atleast one bolt assembly for fastening the first tensioning rail to thefirst side plate and to the at least one angle box of the firsttensioning assembly. The system also includes a second tensioningassembly operatively connectable to the second side plate. The secondtensioning assembly includes a second tensioning rail mountable to theinner surface of the second side plate and connectable to a secondportion of the screen media, at least one angle box mountable to theouter surface of the second side plate, at least one bolt assembly forfastening the second tensioning rail to the second side plate and to theat least one angle box of the second tensioning assembly. Each boltassembly includes a bolt connectable to one of the first and secondtensioning rails, one of the first and second side plates and one of theangle boxes, a nut threadably engaged with the bolt for retaining thebolt to one of the angle boxes, and a shoulder bolt secured to aterminal end of the bolt. The shoulder bolt serves to prevent the nutfrom becoming physically separated from the bolt. Each angle boxincludes an aperture defined therein sized to allow the bolt assemblyunobstructed passage therethrough, and a movable plate with a cutoutformed therein. The cutout is sized larger than the bolt but smallerthan the nut. The movable plate is movable between a bolt-securingposition and a bolt-releasing position. In the bolt-securing position,the movable plate partially occluding the aperture in the angle box withthe cutout aligned with the aperture in the angle box such that when onebolt of the bolt assembly is tightly fastened to the angle box with onenut of the bolt assembly, one of the first and second tensioning railsis drawn tightly against the inner surface of the first and second siderail thereby applying a tensile force to one of the first or secondportions of the screen media. In the bolt-releasing position, themovable plate being positioned so as to provide unobstructed access tothe aperture in the angle box such that the bolt assembly can bedetached from the angle box without requiring disassembly of the boltassembly.

In yet another broad aspect of the invention, there is provided avibrating-type machine which has a frame that includes a deck frame forsupporting screen media, and a pair of spaced apart first and secondside plates attached to the frame. Each side plate has an inner surfaceand an outer surface. The machine is further provided with a mechanismfor imparting vibratory movement to the frame, screen media positionablebetween the first and second side plates and a tensioning system forretaining screen media between the first and second side plates. Theside tensioning system includes a first tensioning assembly operativelyconnectable to the first side plate. The first tensioning assemblyincludes a first tensioning rail mountable to the inner surface of thefirst side plate and connectable to a first portion of the screen media,at least one angle box mountable to the outer surface of the first sideplate, and at least one bolt assembly for fastening the first tensioningrail to the first side plate and to the at least one angle box of thefirst tensioning assembly. The system also includes a second tensioningassembly operatively connectable to the second side plate. The secondtensioning assembly includes a second tensioning rail mountable to theinner surface of the second side plate and connectable to a secondportion of the screen media, at least one angle box mountable to theouter surface of the second side plate, at least one bolt assembly forfastening the second tensioning rail to the second side plate and to theat least one angle box of the second tensioning assembly. Each boltassembly includes a bolt connectable to one of the first and secondtensioning rails, one of the first and second side plates and one of theangle boxes, a nut threadably engaged with the bolt for retaining thebolt to one of the angle boxes, and a shoulder bolt secured to aterminal end of the bolt. The shoulder bolt serves to prevent the nutfrom becoming physically separated from the bolt. Each angle boxincludes an aperture defined therein sized to allow the bolt assemblyunobstructed passage therethrough, and a movable plate with a cutoutformed therein. The cutout is sized larger than the bolt but smallerthan the nut. The movable plate is movable between a bolt-securingposition and a bolt-releasing position. In the bolt-securing position,the movable plate partially occluding the aperture in the angle box withthe cutout aligned with the aperture in the angle box such that when onebolt of the bolt assembly is tightly fastened to the angle box with onenut of the bolt assembly, one of the first and second tensioning railsis drawn tightly against the inner surface of the first and second siderail thereby applying a tensile force to one of the first or secondportions of the screen media. In the bolt-releasing position, themovable plate being positioned so as to provide unobstructed access tothe aperture in the angle box such that the bolt assembly can bedetached from the angle box without requiring disassembly of the boltassembly.

In another broad aspect, there is provided a side tensioning assemblyfor retaining screen media to a side plate in a vibrating-type screeningmachine. The side plate has an aperture, an inner surface and an outersurface. The side tensioning assembly includes a tensioning railmountable to the inner surface of the side plate and connectable to aportion of the screen media, at least one angle box connected to theouter surface of the side plate, and at least one bolt assembly forfastening the tensioning rail to the side plate and to the at least oneangle box. The at least one bolt assembly includes a bolt connectable tothe tensioning rail, the side plate and the at least one of angle box, anut threadably engaged with the bolt for retaining the bolt to the atleast one the angle box, and a shoulder bolt secured to a terminal endof the bolt. The shoulder bolt is sized to prevent the nut from becomingphysically separated from the bolt. At least one angle box including acutout formed therein sized larger than the bolt but smaller than thenut. The angle box is movable relative to the side plate between abolt-securing position and a bolt-releasing position. In thebolt-securing position, the angle box partially occludes the aperture inthe side plate with the cutout aligned with the aperture in the sideplate such that when the bolt is tightly fastened to the angle box withthe nut, the tensioning rail is drawn tightly against the inner surfaceof the side rail thereby applying a tensile force to the portion of thescreen media. In the bolt-releasing position, the angle box ispositioned so as to provide unobstructed access to the aperture in theside plate such that the bolt assembly can be detached from the sideplate without requiring disassembly of the bolt assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the present invention shall be more clearlyunderstood with reference to the following detailed description of theembodiments of the invention taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a top left perspective view showing a screen media panel beingretained between a pair of opposed side plates of a vibrating-typescreening machine by a side tensioning system having a first and secondtensioning assemblies, according to an embodiment of the presentinvention;

FIG. 2 is a side elevation view of the screen media, the side plates andthe first and second tensioning assemblies shown in FIG. 1;

FIG. 3 is an end view of the screen media, the side plates and thesecond tensioning assembly in FIG. 1;

FIG. 4 is an isolated end view of one of the side plates shown in FIG.1;

FIG. 5A is a magnified end view of an angle box of the first tensioningassembly illustrated in FIG. 1 shown mounted to a portion of the sideplate with a movable plate of the angle box occupying a bolt-securingposition;

FIG. 5B is another magnified end view of the angle box and the sideplate similar to that illustrated in FIG. 5A, except that the movableplate is now shown occupying a bolt-releasing position;

FIG. 5C is a perspective view of the angle box and side plate shown inFIG. 5A;

FIG. 6 is a cross-sectional view of the angle box and side plate shownin FIG. 5A taken along line “6-6”;

FIG. 7 is an isolated and magnified, side elevation view of a boltassembly of the first tensioning assembly illustrated in FIG. 1 shownconnected to a tensioning rail;

FIG. 8 is an isolated perspective view of the bolt assembly showing thecarriage bolt exploded from the shoulder bolt;

FIG. 9 is a partially exploded, top left perspective view showing thescreen media and a plurality of angle boxes of the first tensioningassembly carried on the side plate shown in FIG. 1 with the tensioningrail and a plurality of bolt assemblies exploded therefrom;

FIG. 10A is a magnified perspective view of one of the plurality ofangle box assemblies illustrated in FIG. 9 showing the angle boxreceiving a bolt therethrough, the flange nut on the bolt being loosenedso as to provide clearance between the flange nut and the movable plate,and the movable plate occupying the bolt-releasing position;

FIG. 10B is a magnified perspective view of one of the plurality ofangle box assemblies similar to that shown in FIG. 10A, except that themovable plate is now shown occupying the bolt-securing position;

FIG. 10C is a magnified perspective view of one of the plurality ofangle box assemblies similar to that shown in FIG. 10B, except that theflange nut on the bolt is now tightened so that it tightly pressesagainst the movable plate;

FIG. 11 is a magnified side elevation view of the encircled portion “11”indicated in FIG. 2, showing the first tensioning assembly tying thescreen media to one of the side plates of the screening machine; and

FIG. 12 is a top left perspective view showing a screen media panelbeing retained between a pair of opposed side plates of a vibrating-typescreening machine by a tensioning system having a first and secondtensioning assemblies, according to an alternative embodiment to thatshown in FIG. 1;

FIG. 13 is a side elevation view of the screen media, the side platesand the first and second tensioning assemblies shown in FIG. 12;

FIG. 14 is an end view of the screen media, the side plates and thesecond tensioning assembly in FIG. 12;

FIG. 15A is a magnified end view of an angle box of the first tensioningassembly illustrated in FIG. 12 shown mounted to a portion of the sideplate with a movable plate of the angle box occupying a bolt-securingposition;

FIG. 15B is another magnified end view of the angle box and the sideplate similar to that illustrated in FIG. 15A, except that the movableplate is now shown occupying a bolt-releasing position;

FIG. 16 is a cross-sectional view of the angle box and side plate shownin FIG. 15A taken along line “16-16”;

FIG. 17 is a partially exploded, top left perspective view showing thescreen media and a plurality of angle boxes of the first tensioningassembly carried on the side plate shown in FIG. 1 with the tensioningrail and a plurality of bolt assemblies exploded therefrom;

FIG. 18A is a magnified perspective view of one of the plurality ofangle box assemblies illustrated in FIG. 17 showing the angle boxreceiving a bolt therethrough, the flange nut on the bolt being loosenedso as to provide clearance between the flange nut and the movable plate,and the movable plate occupying the bolt-releasing position;

FIG. 18B is a magnified perspective view of one of the plurality ofangle box assemblies similar to that shown in FIG. 18A, except that themovable plate is now shown occupying the bolt-securing position;

FIG. 18C is a magnified perspective view of one of the plurality ofangle box assemblies similar to that shown in FIG. 18B, except that theflange nut on the bolt is now tightened so that it tightly pressesagainst the movable plate;

FIG. 19 is a magnified side elevation view of the encircled portion “19”indicated in FIG. 13; showing the first tensioning assembly tying thescreen media to one of the side plates of the screening machine;

FIG. 20A is a magnified end view of an angle box mounted to a sideplate, the angle box being provided with an alternate movable plate tothat illustrated in FIG. 15A, the movable plate being shown in abolt-securing position; and

FIG. 20B is another magnified end view of the angle box and the sideplate similar to that illustrated in FIG. 20A, except that the movableplate is now shown occupying a bolt-releasing position;

FIG. 20C is a side elevation view of the angle box and side plateillustrated in FIG. 20A;

FIG. 21 is a top right perspective view of a vibrating-type screeningmachine employing they side tensioning system shown in FIG. 1;

FIG. 22A is a magnified end view of an angle box in accordance withanother embodiment of the present invention shown releasably mounted toa portion of a side plate, the angle box occupying its bolt-securingposition;

FIG. 22B is a perspective view the angle box and side plate shown inFIG. 22A;

FIG. 23A is a perspective view of the angle box and side plateillustrated in FIG. 22A showing a bolt assembly inserted through anaperture defined in the side wall and the movable angle box explodedfrom the side plate and occupying a bolt-releasing position;

FIG. 23B is another perspective view of the angle box and side platesimilar to that shown in FIG. 23A, except that the movable angle box isnow shown occupying its bolt-securing position and receiving a bolttherethrough, the flange nut on the bolt being loosened so as to provideclearance between the flange nut and the movable angle box; and

FIG. 23C is another perspective view of the angle box and side platesimilar to that shown in FIG. 23A, except that the movable angle box isnow shown occupying its bolt-securing position and receiving a bolttherethrough, the flange nut on the bolt being loosened so as to provideclearance between the flange nut and the movable angle box;

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

The description which follows, and the embodiments described therein areprovided by way of illustration of an example, or examples of particularembodiments of principles and aspects of the present invention. Theseexamples are provided for the purposes of explanation and not oflimitation, of those principles of the invention. In the descriptionthat follows, like parts are marked throughout the specification and thedrawings with the same respective reference numerals.

Referring to FIG. 21, there is shown a side tensioning system generallydesignated with reference numeral 20. The side tensioning system 20 isused to securely tie, hold or retain screen media 22 (in the nature oftwo screen media panels 400 and 402 disposed side-by-side) between twoopposing side plates 404 and 406 attached to a frame 408 of avibrating-type screening machine 410. The frame 408 includes a singledeck frame 412 which extends between the side plates 404 and 406 andwhich serves to support the screen media panels 400 and 402. The frame408 is operatively connected to a mechanism 414 that is operable toimpart vibratory movement to the frame 408 (and the side plates 404 and406), in a manner known to those skilled in the art such that no furtherdescription is required. It should be appreciated that thevibrating-type screening machine 406 shown in FIG. 21 is provided merelyas an example of the type of screening machine which could employ thetensioning system 20. It is not intended that use of the tensioningsystem 20 be limited to the vibrating-type screening machine 406 shownin FIG. 21. The tensioning system 20 could be employed with othervibrating-type screening machines.

For purposes of better illustrating the invention and facilitating thedescription thereof, the side tensioning system 20 is shown in FIGS. 1to 3 mounted between two side plates 22 and 24. The side plates 22 and24 are intended to be simplified representations of the side plates 400and 402, with extraneous components removed so as not distract from thecomprehension of the invention. Accordingly, the description of the sidetensioning system 20 that follows below is made with reference to sideplates 24 and 26.

In the embodiment shown in FIGS. 1 to 3, the screen media 22 takes theform of a single screen media 28 fabricated from wire cloth. In otherembodiments, the screen media panel could be made of rubber,polyurethane, metal or other suitable materials selected based on theparticular application and material to be screened. The screen mediapanel 28 provided with a plurality of apertures (not shown) of apredetermined size selected based on the desired material to bescreened.

The screen media panel 28 includes a top surface 30 and a bottom surface32, and has a generally rectangular shape when seen in plan view, whichis defined by a pair of relatively long, opposed edges 34 and 36 and apair of relatively short, opposed edges 38 and 40. Affixed to eachopposed short edge 38 and 40, is a generally U-shaped tensioning hook42, 44, respectively. Each hook 42, 44 has a first arm portion 46, asecond arm portion 48 and intermediate portion 50 which joins the firstarm portion 46 to the second arm portion 48 (as bets shown in FIG. 11).The first arm portion 46 serves as an anchor point for the long edge 34or 36 of the screen media panel 28. The second arm portion 48 isoriented to extend away from the top surface 30 of the screen mediapanel 28. As will be explained in greater detail below, tensioning rails52 and 54 which form part of the side tensioning system 20 will engagethe intermediate portions 50 of the tensioning hooks 42 and 44 totightly retain the screen media panel 28 in position, on a suitablesupport structure (not shown, but generally similar to the deck frame412 shown in FIG. 21) and between the side plates 24 and 26. When thusretained, the screen media panel 28 bulges slightly upwardly, its topsurface 30 adopting a gentle convex contour shaped by the supportstructure.

Referring now to FIGS. 2 and 4, each side plate 24, 26 is rectangularand has an outer surface 56 and an inner surface 58. Each side plate 24,26 is further provided with a series of differently-sized aperturesformed therein disposed in a particular arrangement. More specifically,such apertures are arranged in four distinct aperture groupings 60, 62,64 and 66 with each aperture grouping being associated with one boltassembly 68 and one angle box 70 which form part of the side tensioningsystem 20. Each grouping 60, 62, 64 and 66 includes a relatively, largecentral aperture 72 flanked on either side by a relatively smallaperture 74. The central apertures 72 are located roughly midway betweenthe top and bottom edges 76 and 78 of each side plate 24, 26 and thesmall apertures 74 are offset from the central aperture 72 such thatthey are disposed above center of the aperture 72. It will beappreciated that apertures 72 and 74 formed on actual side plates (suchas side plates 404 and 406) of a vibrating-type screening machine wouldbe located above the bottom edge of the side plate, and not necessarilymidway between the top and bottom edges.

In other embodiments, the number of aperture groupings could beincreased or decreased as necessary to accommodate a greater or lessernumber of bolt assemblies and angle boxes.

Welded to the inner surface 58 of each side plate 24 and 26 at alocation below the aperture groupings 60, 62, 64 and 66, is alongitudinal angle member 80. Each angle member 80 extends from onelateral edge 82 of the side plate 24, 26 to the other lateral edge 84(see FIGS. 2 and 11). It will be appreciated that in an actualvibrating-type screening machine the angle members would be provided insections and would not necessarily extend from one lateral edge of aside plate to another. This can be seen in the vibrating-type screeningmachine shown FIG. 21 where two screen media panels 400 and 402 andtheir associated tension rails are arranged side-by-side.

Each angle member 80 includes a first arm 84 and a second arm 86 joinedto the first arm 84. The first arm 84 abuts the inner surface 58 of theside plate 24, 26, while the second arm 86 projects from the innersurface 58 to define a horizontal shelf 88 (labelled on FIG. 11) whichsupports the tensioning hook 42, 44 when the screen media panel 28 issecured top the side plates 24 and 26 by the tensioning system 20.

Referring to FIG. 2, the side tensioning system 20 can be seen to have afirst tensioning assembly 90 associated with side plate 24 and a secondtensioning assembly 92 associated with side plate 26. The firsttensioning assembly 90 includes the tensioning rail 52, a plurality ofbolt assemblies 68 and a corresponding plurality of angle boxes 70(visible in FIG. 1). Similarly, the second tensioning assembly 92includes the tensioning rail 54, a plurality of bolt assemblies 68 and acorresponding plurality of angle boxes 70 (visible in FIG. 3). In theembodiment shown in FIG. 1, each tensioning assembly 90, 92 has fourbolt assemblies 68 and four angle boxes 70. In other embodiments, thetensioning assemblies could be provided with a greater or lesser numberof bolt assemblies and angle boxes.

The first and second tensioning subassemblies 90 and 92 are identical toeach other in all respects, except that they are deployed in a mirrorimage configuration on the side plates 24 and 26. Accordingly, for thepurposes of this specification, it will suffice to describe the firsttensioning assembly 90 only and such description will be equallyapplicable to the second tensioning assembly 92.

With reference to FIGS. 5A, 5B, 5C and 6, the angle box assembly 70 willnow be described in greater detail. The angle box 70 has a roughlyhexagonal, flanged, base portion 94 which can be considered to form theback of the angle box and a hollow, wedge like structure 96 whichprojects from the base portion 94 and is integrally formed therewith,and can be understood to form the front of the angle box. The angle box70 is not fully closed, its back is open to allow access to the space Sdefined by the wedge-like structure 96 (visible in FIG. 6).

In this embodiment, the flanged base portion 94 is shown be distinctfrom the wedge-like structure 96. This need not be the case in everyapplication. In alternative embodiments, the angle box could be formedwithout a defined flange portion. For example, it may be possible toreplace the flange portion with mounting tabs or simply configure thewedge-like structure to attach directly to the side plate. Othermodifications to the angle box are possible and the application of theprinciples of the present invention is not limited to those angle boxesillustrated in the drawings.

As best shown in FIG. 5A, the base portion 94 is defined by a top flangeportion 98, a bottom flange portion 100, a pair upper lateral angledflange portions 102 and 104, and a pair of lower lateral angled flangeportions 106 and 108. The top flange portion 108 extends between theupper lateral flange portions 102 and 104. The flange portions 102 and104 extend downwardly away from the top flange 108 in a divergingmanner. The upper lateral flange portion 102 meets the lower lateralflange portion 106 at a first juncture 110 and similarly, the upperlateral flange portion 104 joins the lower lateral flange portion 108 ata second juncture 112. The bottom flange portion 110 extends between thelower lateral flange portions 106 and 108.

Adjacent each juncture 110, 112, the base portion 94 has apertures (notshown) which are alignable with the small apertures 74 of an aperturegrouping in one of the side plate 24 and 26. The apertures formed in thebase portion 94 are sized to receive small bolts 114 therethrough topermit the angle box 70 to be securely mounted to side plate 24.

As best shown in FIG. 6, the wedge-like structure 96 is defined by two,spaced apart, lateral triangular portions 118 (visible in FIGS. 5A and5B) and 120, a relatively short, upper wall 122 and a relatively long,lower wall 124. The lateral triangular portions 118 and 120 stand proudof the base portion 94. The lateral triangular portion 118 bounds andjoins the upper wall 122 and the lower wall 124 on one side, while thelateral triangular portion 120 bounds and connects to the upper wall 122and the lower wall 124 on the opposite side. The upper wall 122 extendsforwardly of the base portion 94 at a slight decline angle as measuredfrom a notional horizon. The lower wall 124 meets with the upper wall122 where the latter terminates. The lower wall 124 extends downwardlyfrom the upper wall 122 at a right angle to join the base portion 94. Alarge circular aperture 126 is defined in the lower wall 124. It opensonto, and provides access to, the space S defined by the wedge-likestructure 96. The aperture 126 is sized larger than the largest widthdimension of the bolt assembly 68 along its entire length (i.e. largerthan the diameter of the flange nut 184) so that the bolt assembly 68can freely pass through the aperture 126 unhampered without disassembly.In this embodiment, the diameter of the aperture 126 measures 2 in. Inother embodiments, the aperture 126 could be sized or configureddifferently. For example, in alternative embodiments, the aperture couldbe oval, oblong, square, rectangular, or a different shape, provided thesize of the aperture remains larger than the largest width dimension ofthe bolt assembly 68 along its entire length (i.e. larger than thediameter of the flange nut 184).

It should be appreciated that the sizing of the aperture 126 to belarger than the largest width dimension of the bolt assembly 68 alongits entire length, represents a stark departure from prior art angleboxes in known tensioning assemblies. Such angle boxes are typicallyprovided with an oblong aperture which is sized sufficiently large toallow insertion therethrough of a bolt, but is not large enough to allowthe arrangement of washer and nut used to fasten the bolt to fit throughthe oblong aperture. As a result of this design, this type of knowntensioning assembly requires the arrangement of washer and nut to bedisengaged (and physically separated) from the bolt, before the bolt canbe removed from the angle box—thereby leading to loose parts.

The angle box 70 is further provided with means for securing the boltassembly 68 and preventing it from disengaging from the angle box 70. Inthis embodiment such bolt securing means are embodied in a movable platein the nature of a swiveling plate 128 which may be moved between abolt-securing position 130 and a bolt-releasing position 132. Theswiveling plate 128 has a vaguely square shape which is defined by anupper margin 134, a lower margin 136 and opposed lateral margins 138 and140 which run between the upper and lower margins 134 and 136, joiningone to the other. In other embodiments, the swiveling plate could beshaped differently.

At a location adjacent the lateral margin 140 proximate to where thelateral margin 140 meets the upper margin 134, a narrow oblong slot 141is cut into the swiveling plate 128. The oblong slot 141 runs more thanmidway down the lateral margin 140, but does not extend as far as thecorner defined by the juncture of the lateral margin 140 and the lowermargin 136. The oblong slot 141 serves as a track for guiding themovement of the swiveling plate 128 relative to a pivot pin 142 retainedtherein. As best shown in FIG. 5C, the pivot pin 142 has a threaded topportion 143 and an unthreaded bottom portion 144 which is of largerdiameter than the top portion 143. The bottom portion 144 is welded tothe wedge-like structure 96 at a site along the lateral triangularportion 120. The top portion 143 of the pivot pin 142 is captivelyretained within the slot 141 by a washer 145, a wave washer 146, and anut 147. In other embodiments, the pivot pin 142 could be attached tothe wedge-like structure 96 at a different site, for instance, at a sitelocated along the lateral triangular portion 118. As explained ingreater detail below, it is the oblong slot 141 and pivot pin 142arrangement which allows the swiveling plate 128 to travel between abolt-securing position 130 and a bolt-releasing position 132.

A rather significant, elongated cutout 150 having a shape not unlikethat of a thumb when viewed in profile, is formed within the swivelingplate 128. The cutout 150 bites deeply into the lower margin 136 at alocation roughly midway between the lateral margins 138 and 140, andextends upwardly about halfway into the swiveling plate 128. The shapeof the cutout 150 can be seen to be defined substantially by edgeportions 152, 154 and 156. The edge portion 152 extends from the lowermargin 136 generally upwardly and away from the lateral margin 140 in amanner that follows a large smoothly-radiused contour. The edge portion152 terminates where the semi-circular edge portion 154 begins. The edgeportion 156 extends downwardly from the edge portion 154 curving ingently toward the lateral margin 138 as it nears the lower margin 136.The width of the cutout 150 is larger than the diameter of the threadedportion of a carriage bolt 180 of the bolt assembly 68, but it is sizedsmaller than a flange nut 184 of the bolt assembly 68.

Referring to specifically FIG. 5A, when the swiveling plate 128 is inthe bolt-securing position 130, the pivot pin 142 is at the top end ofthe oblong slot 141, the swiveling plate 128 is superimposed over thelower wall 124 of the wedge-shaped structure 96 such that itsubstantially overlaps with it and significantly occludes the centralaperture 126 formed in the lower wall 124. As a result, the openingdefined by the central aperture 126 is severely constricted, and is nowreduced to the size of the cutout 150.

Referring specifically to FIG. 5B, to move the swiveling plate 128 tothe bolt-releasing position 132, the swiveling plate 128 is urged toslide upwards while being pivoted in a clockwise direction approximately45 degrees relative to a notional vertical axis until the bottom end ofthe oblong slot 141 abuts the pivot pin 144. At that point the swivelingplate 128 no longer occludes the central aperture 126 formed in thelower wall 124, leaving the opening defined by the central aperture 126fully exposed to revert back to its full size.

During assembly of the side tensioning system 20, the angle box 70 isplaced on the side plate 24 with the flange portions 98, 100, 102, 104,106 and 108 abutting the outer surface 56 of the side plate 24 or 26.The apertures adjacent each juncture 110 and 112 are aligned with theapertures 74 of an aperture grouping in one of the side plate 24 and 26and small bolts 114 are inserted through the aligned apertures such thatthe free ends protrude beyond the outer surface 56 of the side plate 24.The free ends of the bolts 114 are then secured with nuts 158. While theangle box 70 can be replaced in the event of excessive wear and tear ordamage, it is not intended that the angle box be detached from the sideplate 24 or 26 when replacing the screen media 22.

When the angle box 70 is mounted to the side plate 24, the aperture 126in the angle box 70 aligns with one of the apertures 72 in the sideplate 24 or 26 along a line T (shown in FIG. 6) which represents thedirection of the tensioning force applied by the side tensioning system20.

Referring now to FIG. 7, the tensioning rail 52 is described. Thetensioning rail 52 is a longitudinal sheet member 160 formed with aplurality of bent portions—namely, first lower bent portion 162, secondintermediate bent portion 164, a third intermediate portion 166, and afourth upper bent portion 168. The first lower bent portion 162 isrelatively short and can be seen to extend at a gentle incline upwardlytoward the second intermediate bent portion 164. When the tensioningsystem 20 is deployed, it is the terminal end 170 of the first lowerbent portion 162 that engages with the tensioning hook 42, 44 of thescreen media 28.

At the juncture where the first lower bent portion 162 meets the secondintermediate bent portion 164, the sheet member 160 bends sharplyupwards and away from the first lower bent portion 162. The secondintermediate bent section 164 is disposed between the first and thirdbent portions 162 and 166. The third intermediate portion 166 is thelongest portion and it is formed by bending the sheet member 160 back inthe direction of the first lower bent portion 162. Defined in the thirdintermediate bent portion 166 at a location slightly away from the sitewhere the second and third bent portions 164 and 166 meet, are aplurality of square apertures (not shown). In this embodiment, theplurality of square apertures includes four square apertures—the numberof square apertures corresponds to the number of bolt assemblies 68included in the first tensioning assembly 90. The center-to centerspacing between each square aperture is corresponds to the center-tocenter spacing of the central apertures 72 formed in the side plate 24.The square aperture is sized to accommodate therein a portion of thebolt assembly 68 that has a correspondingly square cross-section.

The sheet member 160 is bent one final time still towards the firstlower bent portion 162 to create the fourth upper bent portion 168. Whenthe tensioning system 20 is deployed, it is the terminal end 172 of thefourth upper bent portion 162 that bears against the inner surface 58 ofthe side plate 24.

Referring now to FIGS. 7 and 8, the bolt assembly 68 includes a carriagebolt 180, a half nut 182, a flange nut 184 and a shoulder bolt 186. Thecarriage bolt 180 has a rounded bolt head 188, a neck portion 190disposed immediately adjacent the bolt head 188 and a shank portion 192.The neck portion 190 has as square cross-section which is sized to fitin the square apertures defined in the third intermediate bent portion166 of the sheet member 160. The shank portion 192 extends away from theneck portion 190. The shank portion 192 is threaded along its entirelength to allow the half nut 182 and the flange nut 184 to traveltherealong. In this embodiment, the carriage bolt is 5.5 in. long andthe diameter of its shank portion 192 is 0.75 in. In other embodiments,a different size carriage bolt could be used.

In contrast to the bolts used in some prior art side tensioningassemblies, the carriage bolt 180 is formed with a blind threaded bore206 which extends into the terminal end 207 of shank portion 192. Theblind bore 206 is adapted to receive a portion of the shoulder bolt 186.

While it is generally preferred that a carriage bolt be used, in otherembodiments, different types of bolts could be used in the boltassembly.

The half nut 182 serves to secure the carriage bolt 180 to thetensioning rail 52 and to ensure that when disconnecting the screenmedia from the side plates 24 and 26 for replacement, the tensioningrail 52 remains adjacent the bolt head 188 and does not travel along thecarriage bolt 180. When assembling the bolt assembly 68 to thetensioning rail 52, the half nut 182 is tightened up against the neckportion 190. While it is generally preferred that the bolt assemblyinclude the half nut 182, in certain alternative embodiments, the halfnut could be omitted from the bolt assembly.

As will be explained in greater, the flange nut 184 in collaborationwith the carriage bolt 180, the tensioning rail 52 and the angle box 70serves to create the tension that holds the screen media 22 in placebetween the side plates 22 and 24. More specifically, the flange nut 184can be made to travel along the threaded shank portion 192 of thecarriage bolt 180 and urged to abut the swiveling plate 128 when it isin its bolt-securing position 130. By tightening the flange nut 184, thecarriage bolt 180 is placed in tension and the tensioning rail 52 isfurther drawn into the side plate 24 causing the screen media panel 28to be more tautly held.

In this embodiment, the flange nut 184 replaces the separate washer andnut arrangement used in known tensioning systems, thereby reducing thenumber of parts which make up the fastening hardware of the tensioningsystem. The flange nut 184 is sized smaller than the diameter of thecentral aperture 126 in the wedge-shaped structure 96 such that when theflange nut 184 is threaded onto the shank portion 192 and the swivelingplate 128 is in its bolt-releasing position 132, the carriage bolt 180can be easily pulled out of the angle box 70. However, the size of theflange nut 184 is greater than the size of the cutout 150 such when thebolt assembly 68 is fitted into the angle box 70 and the swiveling plate128 is in the bolt-securing position 130, the flange nut 184 blocks thecarriage bolt 180 from being pulled out of the angle box 70. In thisembodiment, the width of the flange nut is 1.62 in. In otherembodiments, the flange nut could be replaced with another suitable nutor with a nut and a washer.

The shoulder bolt 186 includes a bolt head portion 194, a threaded shankportion 196 and an unthreaded shoulder portion 198 disposed betweenportions 194 and 196. Integrally formed within the bolt head portion 194is a hex socket 200. The bolt head portion 194 is also provided withwraparound knurling 202. The diameter of the shoulder portion 198 issmaller than that of the bolt head portion 194 such that it defines aflange 204. The diameter of the threaded shank portion 196 is smallerthan that of the shoulder portion 198. The threaded shank portion 196 issized to mate with the blind threaded bore 206 formed in the shankportion 192 of the carriage bolt 180.

With the diameter of the bolt head portion 194 being sized larger thanthe diameter of the apertures (not shown) formed in the half nut 182 andthe flange nut 184, when the shoulder bolt 186 is attached to thecarriage bolt 180, the flange 204 formed in the shoulder bolt 186prevents both the flange nut 184 from getting physically separated fromthe bolt assembly 68. Should the the flange nut 184 become disengagedfrom the shank portion 192 of the carriage bolt 180, it would slide ontothe shoulder portion 198 of the shoulder bolt 186 and be captivelyretained on the shoulder bolt 186 by the flange 204 defined by the bolthead portion 194. As a further advantage, the shoulder portion 196 ofthe shoulder bolt 186 provides a structure about which the flange nut 18may freely spin in the event that the tool used to disengage the flangenut 184 continues to impart rotary motion to the flange nut 184 once ithas become disengaged from the threaded shank portion 192 of the bolt180.

As a result, this arrangement permits the tensioning rail 52 andfastening hardware associated therewith to be removed or installed (asthe case may be) as a single component or unit, without having aplurality of loose parts floating around when replacing the screen media22 as is the case with prior art tensioning systems. Since the fasteninghardware does not need to be assembled or disassembled every time thetensioning assembly is installed or removed, the deployment or removalprocess tends to be more streamlined and simplified. Significant timesavings can be realized. Moreover, because of such efficiencies, where atensioning system in accordance with the principles of the presentinvention is employed, it is now possible for a single workman to carryout install or remove screen media. As an additional benefit, since thefastening hardware is no longer physically separated from the boltassembly, it tends not to get lost and require replacement, leading tocost savings in respect of spare parts.

The following is a short description of how the bolt assembly 68attaches to the tensioning rail 52. First, the carriage bolt 180 isinserted into one of the square apertures (not shown) defined in thesheet member 160 until the bolt head portion 194 of the carriage bolt180 abuts the third intermediate bent portion 166 and the neck portion190 is securely received in the square apertures. Thereafter, the halfnut 182 is threaded onto the carriage bolt 180 and urged to travel untilit abuts the neck portion 190 of the carriage bolt. Next, the flange nut184 is threaded onto the carriage bolt 180. As a final step, theshoulder bolt 186 is fastened onto the terminal end 206 of the shankportion 192.

Having described all the components of the tensioning system 20, adescription of an exemplary deployment of the tensioning system 20 toretain the screen media 22 between the side plates 24 and 26 now followswith reference to FIGS. 9, 10A, 10B, 10C and 11. As a preliminary step,the screen media panel 28 is laid onto of the deck frame (not shown) ofthe vibrating-type screening machine (not shown) with its tensioninghooks 42 and 44 supported on the horizontal shelf 88 defined by theangle member 80 mounted to the side plates 24 and 26. The swivelingplate 128 on each of the angle boxes 70 associated with the side plates24 and 26 is moved from its bolt-securing position 130 to itsbolt-releasing positions 132 so as to provide full access to the centralaperture 126 (see FIG. 9). Also, the flange nut 184 of each of the boltassemblies 80 is threaded towards the shoulder bolt 196. In FIGS. 9, 10Aand 10B, the flange nut 184 is shown moved right up to the terminal end206 of the shank portion 192 for purposes of illustration. In practice,it may not be necessary to move the flange nut 184 that far down theshank portion 192, provided that sufficient clearance between the flangenut 184 and the wedge-like structure 96 can be obtained when the boltassemblies 68 are mated with the angle boxes 70.

The installation begins with positioning the tensioning rail 52 alongwith its associated tensioning hardware (i.e. the four bolt assemblies68) so that the bolt assemblies 68 are disposed opposite the apertures72 in the side plate 24 and the carriage bolts 180 are orienteddownwardly in the direction of line T (shown in FIG. 6). Thereafter, thebolt assemblies 68 are inserted through the aperture 72 in the sideplate 24 so as to extend through the space S (shown in FIG. 6) definedby the wedge-like structure 96 and project out of the central apertures126 formed in the angle boxes 70. As shown in FIG. 10A, in thisposition, for each bolt assembly 68, the portion of the shank portion192 carrying the flange nut 184 and the shoulder bolt 196 protrudesbeyond the lower wall 124 of the wedge-like structure 96, therebyproviding clearance between the wedge-like structure 96 and the flangenut 184.

It should be mentioned that as bolt assemblies 68 are fitted throughapertures 72 and 124, the tensioning rail 52 is brought closer to theinner surface 58 of the side plate 24. The first lower bent portion 162is received in the gap formed between the arms 46 and 48 of thetensioning hook 42.

Referring now to FIG. 10B, with the bolt assemblies 68 well positionedwithin the angle boxes 70, the swiveling plate 128 of each angle box 70is now moved from its bolt-releasing position 132 to its bolt-securingposition 130. More specifically, the swiveling plate 128 is sliddownwardly guided by the engagement of the walls of the oblong slot 141with the pivot pin 142, while being rotated counter-clockwise about thepivot pin 142. As this occurs, the cutout 150 is brought near thecarriage bolt 180. The edges 152 and 156 of the cutout 150 come intocontact with the shank portion 192 of the carriage bolt 180 and guidethe movement of the swiveling plate 128 to the bolt-securing position130. When in this position, the semi-circular edge 154 serves as a stopfor the shank portion 192.

The foregoing steps are then repeated to deploy the second tensioningassembly 92 associated with the side plate 26.

As a final step, the flange nut 184 in each bolt assembly 68 of thefirst and second tensioning assemblies 90 and 92 is threaded towards itsassociated angle box 70 so that the flange portion 208 of the flange nut184 comes to bear against swiveling plate 128 (see FIG. 10C). The flangenut 184 is further tightened until sufficient tension in the carriagebolt 180 is created. As this occurs, the tensioning rail 52 forcefullyengages the side plate 24 and the tensioning hooks 42, and similarly,the tensioning rail 54 forcefully engages the side plate 26 and thetensioning hooks 44 (see FIG. 11). More specifically, in each case, theterminal end 172 of the fourth upper bent portion 168 abuts the innersurface 58 of the side plate 24 or 26 (as the case may be). Also, ineach case, the terminal end 170 of the first lower bent portion 162bears against the intermediate portion 50 pulling the tensioning hook 42or 44 (as the case may be) towards the side plate 24 or 26. The tensioncreated by the tensioning assemblies 90 and 92 holds the screen media 22tightly between the side plates 24 and 26.

In the embodiment shown in FIGS. 1 to 11 the tensioning assemblies 90and 92 employ angle boxes 70 which are provided with swiveling plates128 that serve to lock the carriage bolts 180. The movement of theswiveling plates 128 combines sliding motion and rotation. However, thisneed not be the case in every application. In other embodiments, theswiveling plates could be replaced with different movable plates whosemovement is limited to translation only (i.e. sliding without anyrotation or angular displacement). An example of such an embodiment isillustrated in FIGS. 12 to 19 which show screen media being held betweentwo opposed side plates using a tensioning system generally designatedwith reference numeral 220. This embodiment uses many of the samecomponents as the earlier described embodiment. To avoid undulyrepeating descriptions of identical components, where a component inthis alternative embodiment is designated using the same referencenumeral as was used for the description of such component in theprevious embodiment, it will be understood that the component in thealternative embodiment is the same as the corresponding component in theprevious embodiment in all material respects, such that the previousdescription of that component can be relied upon for the purposes ofexplaining the alternative embodiment with any variations therefrombeing set forth below. With this in mind, it will be understood thattensioning system 220 ties screen media 22 to the side plates 22 and 24.

The side tensioning system 220 can be seen to have a first tensioningassembly 222 associated with side plate 24 and a second tensioningassembly 224 associated with side plate 26. The first tensioningassembly 222 includes a tensioning rail 52, a plurality of boltassemblies 68 and a corresponding plurality of angle boxes 226 (visiblein FIG. 12). Similarly, the second tensioning assembly 224 includes atensioning rail 54, a plurality of bolt assemblies 68 and acorresponding plurality of angle boxes 226 (visible in FIG. 14). In theembodiment shown in FIG. 12, each tensioning assembly 222, 224 has fourbolt assemblies 68 and four angle boxes 226. In other embodiments, thetensioning assemblies could be provided with a greater or lesser numberof bolt assemblies and angle boxes.

With reference to FIGS. 15A, 15B, 15C and 16, the angle box 226 is nowdescribed in greater detail. The angle box 226 resembles the angle box70 in that it possesses the roughly hexagonal, flanged, base portion 94and the hollow, wedge like structure 96 which projects from the baseportion 94. The difference between the angle box 226 and the angle box70 lies in the fact that angle box 226 uses a different movable platethan the swiveling plate 128 employed by angle box 70. In thisembodiment the movable plate is in the nature of a sliding plate 228which may be moved between a bolt-securing position 230 and abolt-releasing position 232.

The sliding plate 228 has a vaguely rectangular footprint when viewed inplan, which is defined by an upper margin 234, a lower margin 236 andopposed lateral margins 238 and 240 which run between the upper andlower margins 234 and 236, joining one to the other. At a locationadjacent the lateral margin 238 proximate to where the lateral margin238 meets the upper margin 234, a first narrow oblong slot 242 is cutinto the sliding plate 228. The first oblong slot 242 runs down almostthe entire length of the lateral margin 238, terminating at a locationadjacent where the lateral margin 238 meets the lower margin 236. Thesliding plate 228 also has a second oblong slot 244 that is disposedopposite the first oblong slot 242 and formed adjacent the lateralmargin 240. The second oblong slot 244 also runs from a locationadjacent where the lateral margin 240 meets the upper margin 234 to alocation adjacent where the lateral margin 240 meets joins the lowermargin 236. Along most of their respective lengths, the first and secondoblong slots 242 and 244 extend along plane P of the sliding plate 228(shown in FIG. 19). However, the paths of the oblong slots 242 and 244deviate from the plane P where the sliding plate 228 is formed with anupwardly bent or angled portion 246. As best shown in FIG. 19, theangled portion 246 commences roughly three-quarters of the way down thelateral margins 238 and 240 and terminates at the lower margin 236.Configured in this manner the lower margin 236 is carried away from theplane P at an angle of 45 degrees.

The first and second oblong slots 242 and 244 define parallel tracks forguiding the translational movement of the sliding plate 228 relative tofirst and second pins 248 and 250 retained therein, respectively. Eachpin 248, 250 has a threaded top portion 252 and an unthreaded bottomportion 254 which is of larger diameter than the top portion 252. Thebottom portion 254 of the pin 248 is welded to the wedge-like structure96 at a site along the lateral triangular portion 118. Similarly, thebottom portion 254 of the pin 250 is welded to the lateral triangularportion 120 of the wedge-like structure 96. The top portion 252 of eachpin 248, 250 is captively retained within the slot 242, 244,respectively by a nut 256. As explained in greater detail below, it isthe oblong slots 242 and 244 and the pins 248 and 250 which allow thesliding plate 228 to travel between a bolt-securing position 230 and abolt-releasing position 232.

In the center of the angled portion 246, a large section of platematerial is removed to thereby define two spaced apart tabs 258 and 260which accommodate the bottom ends of oblong slots 242 and 244. The spaceG defined between the tabs 258 and 260 opens onto an elongated cutout262 which cuts deeply into the sliding plate 228 at a location adjacentthe roughly midway between the lateral margins 238 and 240, and extendsupwardly about halfway into the main planar portion 264 of sliding plate228. The shape of the cutout 262 can be seen to be defined substantiallyby edge portions 266, 268 and 270. Straight edge portion 266 and 270 aregenerally parallel to each other and are joined to each other by thesemi-circular edge portion 268. The width of the cutout 262 as measuredbetween the edge portions 266 and 270 is larger than the diameter of thethreaded portion of a carriage bolt 180 of the bolt assembly 68, but itis sized smaller than a flange nut 184 of the bolt assembly 68.

Referring to FIG. 15A, when the sliding plate 228 is in thebolt-securing position 230, the pins 248 and 250 are at the top ends ofthe oblong slots 242 and 244, respectively, the sliding plate 228 issuperimposed over the lower wall 124 of the wedge-shaped structure 96such that it substantially overlaps with it and significantly occludesthe central aperture 126 formed in the lower wall 124. As a result, theopening defined by the central aperture 126 is severely constricted, andis now reduced to the size of the cutout 262.

Referring to FIG. 15B, to move the sliding plate 228 to thebolt-releasing position 232, the sliding plate 228 is urged to slideupwards until the bottom ends of the oblong slots 242 and 244 abut thepins 248 and 250, respectively. At that point the sliding plate 228 nolonger occludes the central aperture 126 formed in the lower wall 124,leaving the opening defined by the central aperture 126 fully exposed.It will be appreciated that as the sliding plate 228 moves relative tothe pins 248 and 250, the main planar portion 264 will move generallyparallel to the lower wall 124 of the wedge-like structure 96 until theangled portion 246 of the sliding plate 228 reaches the pins 248 and250. At that stage, the main planar portion 264 will adopt an angledorientation relative to the lower wall 124. When the bottom ends of theoblong slots 242 and 244 make contact with the pins 248 and 250, themain planar portion 264 hangs well over the pins thereby discouragingthe sliding plate 228 from accidentally sliding back towards thebolt-securing position 230 by virtue of the force of gravity alone.

During assembly of the side tensioning system 20, the angle box 226 isfastened to the side plate 24 in the same manner as angle box 70, suchthat no further description is required. When the angle box 226 ismounted to the side plate 24, the aperture 126 in the angle box 226aligns with one of the apertures 72 in the side plate 24 or 26 along aline T (shown in FIG. 19) which represents the direction of thetensioning force applied by the side tensioning system 220.

A description of an exemplary deployment of the side tensioning system220 to retain the screen media 22 between the side plates 24 and 26 nowfollows with reference to FIGS. 17, 18A, 18B, 18C and 19. As apreliminary step, the screen media panel 28 is laid onto of the deckframe (not shown) of the vibrating-type screening machine (not shown)with its tensioning hooks 42 and 44 supported on the horizontal shelf 88defined by the angle member 80 mounted to the side plates 24 and 26. Thesliding plate 228 on each of the angle boxes 226 associated with theside plates 24 and 26 is moved from its bolt-securing position 230 toits bolt-releasing positions 232 so as to provide full access to thecentral aperture 126 (see FIG. 17). Also, the flange nut 184 of each ofthe bolt assemblies 80 is threaded towards the shoulder bolt 196.

The installation begins with positioning the tensioning rail 52 alongwith its associated tensioning hardware (i.e. the four bolt assemblies68) so that the bolt assemblies 68 are disposed opposite the apertures72 in the side plate 24 and the carriage bolts 180 are orienteddownwardly in the direction of line T (shown in FIG. 19). Thereafter,the bolt assemblies 68 are inserted through the aperture 72 in the sideplate 24 so as to extend through the space S (shown in FIG. 6) definedby the wedge-like structure 96 and project out of the central apertures126 formed in the angle boxes 226. As shown in FIG. 18A, in thisposition, for each bolt assembly 68, the portion of the shank portion192 carrying the flange nut 184 and the shoulder bolt 196 protrudesbeyond the lower wall 124 of the wedge-like structure 96, therebyproviding clearance between the wedge-like structure 96 and the flangenut 184.

It should be mentioned that as bolt assemblies 68 are fitted throughapertures 72 and 124, the tensioning rail 52 is brought closer to theinner surface 58 of the side plate 24. The first lower bent portion 162is received in the gap formed between the arms 46 and 48 of thetensioning hook 42.

Referring now to FIG. 18B, with the bolt assemblies 68 well positionedwithin the angle boxes 226, the sliding plate 228 of each angle box 226is now moved from its bolt-releasing position 232 to its bolt-securingposition 230. More specifically, the sliding plate 228 is sliddownwardly guided by the engagement of the walls of the oblong slots 242and 244 with the pin 248 and 250. As this occurs, the cutout 262 isbrought near the carriage bolt 180. The edges 266 and 270 of the cutout262 come into contact with the shank portion 192 of the carriage bolt180 and guide the movement of the sliding plate 228 to the bolt-securingposition 230. When in this position, the semi-circular edge 268 servesas a stop for the shank portion 192.

The foregoing steps are then repeated to deploy the second tensioningassembly 224 associated with the side plate 26.

As a final step, the flange nut 184 in each bolt assembly 68 of thefirst and second tensioning assemblies 222 and 224 is threaded towardsits associated angle box 226 so that the flange portion 208 of theflange nut 184 comes to bear against moving plate 228 (see FIG. 18C).The flange nut 184 is further tightened until sufficient tension in thecarriage bolt 180 is created. As this occurs, the tensioning rail 52forcefully engages the side plate 24 and the tensioning hooks 42, andsimilarly, the tensioning rail 54 forcefully engages the side plate 26and the tensioning hooks 44 (see FIG. 19). More specifically, in eachcase, the terminal end 172 of the fourth upper bent portion 168 abutsthe inner surface 58 of the side plate 24 or 26 (as the case may be).Also, in each case, the terminal end 170 of the first lower bent portion162 bears against the intermediate portion 50 pulling the tensioninghook 42 or 44 (as the case may be) towards the side plate 24 or 26. Thetension created by the tensioning assemblies 222 and 224 holds thescreen media 22 tightly between the side plates 24 and 26 and on thedeck frame (not shown).

In the embodiment shown in FIGS. 12 to 19, the slidable plate 228includes a main planar portion 264 and an upwardly bent or angledportion 246. As mentioned above, the configuration of the sliding plate228 with an angled potion is advantageous in that, when the slidingplate is in the bolt-releasing position 232, it tends to discourage thesliding plate 228 from sliding back toward the bolt-securing position230. While this feature may be useful in certain applications, it neednot be included in every embodiment where a sliding plate is used. Incertain embodiments this feature could be omitted. An example of such anembodiment is shown in FIGS. 20A and 20B wherein an alternate angle boxto angle box 226 is designated generally with reference numeral 280.

The angle box 280 uses many of the same components as angle box 226 andangle box 70. To avoid unduly repeating descriptions of identicalcomponents, where a component in this alternative embodiment isdesignated using the same reference numeral as was used for thedescription of such component in the preferred embodiment, it will beunderstood that the component in the alternative embodiment is the sameas the corresponding component in the preferred embodiment in allmaterial respects, such that the previous description of that componentcan be relied upon for the purposes of explaining the alternativeembodiment with any variations therefrom being set forth below.

The angle box 280 resembles the angle boxes 70 and 226 in that itpossesses the roughly hexagonal, flanged, base portion 94 and thehollow, wedge like structure 96 which projects from the base portion 94.In like fashion to angle box 226, the angle box 280 also employs amovable plate in the nature of sliding plate 282 which is restricted totranslational movement only. The sliding plate 282 can be moved betweena bolt-securing position 284 and a bolt-releasing position 286.

The sliding plate 282 has a generally rectangular footprint when viewedin plan, which is defined by an upper margin 288, a lower margin 290 andopposed lateral margins 292 and 294 which run between the upper andlower margins 288 and 290, joining one to the other. At a locationadjacent the lateral margin 292 proximate to where the lateral margin292 meets the upper margin 288, a first narrow oblong slot 296 is cutinto the sliding plate 282. The first oblong slot 296 runs down almostthe entire length of the lateral margin 292, terminating at a locationadjacent where the lateral margin 292 meets the lower margin 290. Thesliding plate 282 also has a second oblong slot 298 that is disposedopposite the first oblong slot 296 and formed adjacent the lateralmargin 294. The second oblong slot 298 also runs from a locationadjacent where the lateral margin 294 meets the upper margin 288 to alocation adjacent where the lateral margin 294 meets joins the lowermargin 290. In contrast to the first and second oblong slots 242 and 244of slidable plate 228, the oblong slots 296 and 298 do not deviate fromthe plane P of the sliding plate 228 (see FIG. 20C). The slidable plateis not formed with a bent or angled portion such that it extends alongplane P along its entire extent.

The first and second oblong slots 296 and 298 define parallel tracks forguiding the translational movement of the sliding plate 282 relative tofirst and second pins 300 and 302 retained therein, respectively. Eachpin 302, 304 has a threaded top portion 306 and an unthreaded bottomportion 308 which is of larger diameter than the top portion 306 (bestshown in FIG. 20C). The bottom portion 308 of the pin 300 is welded tothe wedge-like structure 96 at a site along the lateral triangularportion 118. Similarly, the bottom portion 308 of the pin 300 is weldedto the lateral triangular portion 120 of the wedge-like structure 96.The top portion 306 of each pin 300, 302 is captively retained withinthe slot 296, 298, respectively by a nut 310. The oblong slots 296 and298 and the pins 300 and 302 which the sliding plate 228 to travelbetween a bolt-securing position 284 and a bolt-releasing position 286.

A rather significant, elongated cutout 312 is formed within the slidingplate 282. The cutout 312 bites deeply into the lower margin 290 at alocation roughly midway between the lateral margins 292 and 294, andextends upwardly about halfway into the sliding plate 282. The shape ofthe cutout 262 can be seen to be defined substantially by edge portions314, 316 and 318. Straight edge portion 314 and 318 are generallyparallel to each other and are joined to each other by the semi-circularedge portion 316. The width of the cutout 312 as measured between theedge portions 314 and 318 is larger than the diameter of the threadedportion of a carriage bolt 180 of the bolt assembly 68, but it is sizedsmaller than a flange nut 184 of the bolt assembly 68.

Referring specifically to FIG. 20A, when the sliding plate 228 is in thebolt-securing position 284, the pins 302 and 304 are at the top ends ofthe oblong slots 296 and 298, respectively, the sliding plate 282 issuperimposed over the lower wall 124 of the wedge-shaped structure 96such that it substantially overlaps with it and significantly occludesthe central aperture 126 formed in the lower wall 124. As a result, theopening defined by the central aperture 126 is severely constricted, andis now reduced to the size of the cutout 262.

Referring specifically to FIG. 20B, to move the sliding plate 282 to thebolt-releasing position 286, the sliding plate 282 is urged to slideupwards until the bottom ends of the oblong slots 296 and 298 abut thepins 300 and 302, respectively. At that point the sliding plate 282 nolonger occludes the central aperture 126 formed in the lower wall 124,leaving the opening defined by the central aperture 126 fully exposed torevert back to its full size.

The deployment of a tensioning assembly which includes angle boxes 280is carried out substantially as described in the context of the sidetensioning system 220 shown in FIGS. 12 to 19, such that no additionaldescription is required.

Other changes could be made to the movable plate of the angle box. Forinstance, in alternative embodiments, the movable plate could beconfigured to slide laterally (i.e. side-to side), diagonally, or in anydirection, instead of an up and down to alternatively, occlude or givefull access to, the central aperture 126 in the wedge-like structure 96.In an embodiment where the movable plate was configured to slidelaterally, the slots formed in the movable plate would be orientedhorizontally instead of vertically. Alternatively, movement of themovable plate could be restricted to rotational movement only.

In other embodiments, the movable plate could be hingedly connected toangle box (or the wedge-like structure). In such an embodiment, themovable plate could be pivoted about the hinge axis to move the platefrom a bolt-securing position (wherein the movable plate is superimposedonto the lower wall 124 of the wedge-like structure 96) to a boltreleasing position (wherein the movable plate is no longer superimposedonto the lower wall 124). Conceivably, the movable plate could beconnected to the angle box by other means. For instance, it could betied or tethered to the angle box with a cable or leash. When in thebolt-releasing position, the plate could be strapped down to the anglebox at a location which does not interfere with access to the centralaperture formed in the wedge-like structure. When required, the platecould be moved to the bolt-securing position where it partiallyobstructs the central aperture, engages the carriage bolt 180 and isacted upon by the flange nut 184.

From the foregoing description, it will be appreciated that thetensioning system fabricated in accordance with the principles of thepresent invention tends to be easy to manufacture. Moreover, theconfiguration of a larger aperture in the angle box and the provision ofa movable plate which can be moved to partially obstruct or fully exposethe large aperture, along with the provision of a tension rail and boltassembly which can be installed or removed altogether without requiringassembly or disassembly (as the case may be) of the fastening hardware,create a tensioning system that tends to be effective, simple and quickto deploy even using a single workman.

All of the embodiments described above make use of an angle box providedwith a movable plate. However, the principles of the present inventioncould be applied differently to similar advantage. For instance, in analternative embodiment, it may be possible to do away with the movableplate in favour of an angle box that is movable relative to the sideplate. This could be implemented in any number of ways. For example, anangle box could be configured with a larger flange portion toaccommodate horizontal or vertical slots that receive pins which areattached to the side plate. In such an embodiment, the slots would serveto guide the movement of the angle box relate to the side plate, in amanner not dissimilar to that with which the first and second slots 242and 244 defined in the movable plate 228 guide the movable platerelative to the stationary angle box 226. In such an embodiment, thecentral aperture would still be sized larger than the largestwidth/diameter dimension of the bolt assembly. The aperture could remaincircular or it could have some other suitable shape, such as akeyhole-shape. Where the aperture is keyhole-shaped, it could beprovided with a narrow opening communicating with a larger opening—suchthat when the angle box is moved to its bolt-releasing position, thelarge opening (which would be sized larger than the bolt assembly) wouldbe aligned with the bolt assembly and would allow the bolt assembly tobe removed, and when the angle box is moved to its bolt-securingposition, the narrow opening (which would be sized smaller than the boltassembly) would be aligned with the angle box and would prevent theremoval of the bolt assembly when the angle box is fastened thereto.

FIGS. 22A, 22B and 23A to 23C illustrate another embodiment of a movableangle box mountable to a side plate. In these drawings, the movableangle box is designated generally with reference numeral 480. For thepurposes of describing the movable angle box 480, it will be necessaryto describe its engagement with a side plate, a tensioning rail and abolt assembly. As these latter components are identical to the sideplate, tensioning rail and bolt assembly described earlier, they will bedesignated with the same reference numeral and the previous descriptionof these components can be relied upon for the purposes of explainingthis alternative embodiment with any variations therefrom being setforth below. With this in mind, it will be understood that movable anglebox 480 forms part of a tensioning assembly that also includes atensioning rail 52 and a bolt assembly 68. Moreover, the movable anglebox 480 is engageable with the side plate 24 and the bolt assembly 68.

Referring now specifically to FIGS. 22A and 22B, the movable angle box480 is now described in greater detail. The angle box 480 has a roughlyhexagonal, flanged, base portion 482 which can be considered to form theback of the angle box and a hollow, wedge like structure 484 whichprojects from the base portion 482 and is integrally formed therewith,and can be understood to form the front of the angle box. The angle box480 is not fully closed, its back is open to allow access to the space(not visible) defined by the wedge-like structure 484.

In this embodiment, the flanged base portion 482 is shown be distinctfrom the wedge-like structure 484. This need not be the case in everyapplication. In alternative embodiments, the angle box could be formedwithout a defined flange portion. For example, it may be possible toreplace the flange portion with mounting tabs or simply configure thewedge-like structure to attach directly to the side plate.

The base portion 482 is generally similar to the base portion 94 of theangle box 70 in that it too is defined by a top flange portion 486, abottom flange portion 488, a pair upper lateral angled flange portions490 and 492, and a pair of lower lateral angled flange portions 494 and496. The top flange portion 486 extends between the upper lateral flangeportions 490 and 492. The flange portions 490 and 492 extend downwardlyaway from the top flange 486 in a diverging manner. The upper lateralflange portion 490 meets the lower lateral flange portion 494 at a firstjuncture 498 and similarly, the upper lateral flange portion 492 joinsthe lower lateral flange portion 496 at a second juncture 500. Thebottom flange portion 488 extends between the lower lateral flangeportions 494 and 496. In contrast to the bottom flange portion 100 ofthe base portion 94, the bottom plane portion 488 does not extendcontinuously, it is interrupted by a cutout 502 which bites into thebottom flange portion 488 and extends substantially into the wedge-likeportion 484.

Adjacent each juncture 498, 500, the base portion 482 has mounting pegs504 formed on its front and rear faces (only the mounting pegs 504 onthe front face of the base portion 482 are visible in FIG. 22B). Themounting pegs 504 are mateable with the small apertures 74 of anaperture grouping in the side plate 24 to attach the moveable angle box480 to the side plate 24.

As best shown in FIG. 22A, the wedge-like structure 484 is defined bytwo, spaced apart, lateral triangular portions 506 and 508, a relativelyshort, upper wall 510 and a relatively long, lower wall 512. The lateraltriangular portions 506 and 508 stand proud of the base portion 482. Thelateral triangular portion 506 bounds and joins the upper wall 510 andthe lower wall 512 on one side, while the lateral triangular portion 506bounds and connects to the upper wall 510 and the lower wall 512 on theopposite side. The upper wall 510 extends forwardly of the base portion482 at a slight decline angle as measured from a notional horizon. Thelower wall 512 meets with the upper wall 510 where the latterterminates. The lower wall 512 extends downwardly from the upper wall510 at a right angle to join the base portion 482.

Extending roughly three-quarters of the way up the lower wall 512, isthe elongate cutout 502. It opens onto, and provides access to, thespace defined by the wedge-like structure 484. The shape of the cutout502 can be seen to be defined substantially by edge portions 514, 516and 518. Straight edge portion 514 and 518 are generally parallel toeach other and are joined to each other by the semi-circular edgeportion 516. The width of the cutout 502 as measured between the edgeportions 514 and 518 is larger than the diameter of the threaded portionof a carriage bolt 180 of the bolt assembly 68, but it is sized smallerthan a flange nut 184 of the bolt assembly 68.

The angle box 480 is further provided with means for tying the angle box480 to the side plate 24. In this embodiment such tying means areembodied in a tether or cable 520 that is attached at one end to the topflange portion 486 and anchored at the other end to the side plate 24.The tether 520 ensures that when the movable angle box 480 is notattached to the side plate 24 by way of its mounting pegs 504, it isnonetheless physically connected to the side plate 24 and will not beotherwise lost or misplaced.

FIGS. 22A and 22B show the movable angle box 480 in a bolt-securingposition 522. In this position, the movable angle box 480 is mounted tothe side plate 24 with the mounting pegs 504 of the movable angle box480 mated with the apertures 74 formed in the side plate 24. The lowerwall 512 of the wedge-shaped structure 484 is arranged such that itsignificantly occludes the aperture 72 formed in the side plate 24. As aresult, the opening defined by the aperture 72 is severely constricted,and is now reduced to the size of the cutout 502. The cutout 502 isaligned with the aperture 74 along a line (similar to line T shown inFIG. 11) which represents the direction of the tensioning force appliedby the side tensioning assembly employing the movable angle box 480.

FIG. 23A shows the movable angle box 480 in a bolt-releasing position524. In that position, the mounting pegs 504 are removed from theapertures 74 in the side plate 24. The movable angle box 480 isdisplaced from the aperture 74 in the side plate 24 such that it nolonger occludes the aperture 74, leaving the opening defined by theaperture 74 fully exposed and unobstructed.

A description of an exemplary deployment of a tensioning assembly usinga movable angle box 480 now follows with reference to FIGS. 23A, 23B and23C. As a preliminary step, the movable angle box 480 is disengaged fromthe side plate 24 in that its mounting pegs 504 are removed from theapertures 74 in the side plate 24, and the movable plate is in abolt-releasing position 524 so as to provide full access to the aperture74 (see FIG. 23A). Also, the flange nut 184 of each of the boltassemblies 80 is threaded towards the shoulder bolt 196.

The installation begins with positioning the tensioning rail 52 (notvisible in FIGS. 23A, 23B and 23C) along with its associated boltassembly. The bolt assembly 68 is disposed opposite the aperture 72 inthe side plate 24 and the carriage bolt 180 is oriented downwardly.Thereafter, the bolt assembly 68 is inserted through the aperture 72 inthe side plate 24 so as to significantly project therefrom. As shown inFIG. 23A, in this position, the portion of the shank portion 192carrying the flange nut 184 and the shoulder bolt 196 protrudes wellbeyond the side wall 24, thereby providing sufficient clearance to allowthe movable angle box 480 to be moved to its bolt-securing position 522without interference from the flange nut 184.

It should be mentioned that as bolt assembly 68 is fitted through theaperture 72, the tensioning rail 52 is brought closer to the innersurface 58 of the side plate 24. The first lower bent portion 162 isreceived in the gap formed between the arms 46 and 48 of the tensioninghook 42.

Referring now to FIG. 23B, the movable angle box 480 is now moved fromits bolt-releasing position 520 to its bolt-securing position 522. Morespecifically, the angle box 480 is moved towards the side plate 24 andpositioned so that the cutout 502 is disposed above the carriage bolt180 in alignment with it. Thereafter, the angle box is lowered so thatthe edges 514, 516 and 518 guide the movement of the angle box 480relative to the carriage bolt 180, with the semi-circular edge 516serving as a stop for the shank portion 192. The mounting pegs 504 arethen aligned with the apertures 74 in the side plate 24 and urged tomate therewith.

As a final step, the flange nut 184 in the bolt assembly 68 is threadedtowards the movable angle box 480 so that the flange portion 208 of theflange nut 184 comes to bear against lower wall 512 of the angle box 480(see FIG. 23C). The flange nut 184 is further tightened until sufficienttension in the carriage bolt 180 is created. As this occurs, thetensioning rail 52 forcefully engages the side plate 24 and thetensioning hook 42. The terminal end 172 of the fourth upper bentportion 168 abuts the inner surface 58 of the side plate 24 (similar tothat which is shown in FIG. 11). Also, the terminal end 170 of the firstlower bent portion 162 bears against the intermediate portion 50 pullingthe tensioning hook 42 towards the side plate 24. The tension created bythe tensioning assembly holds the screen media 22 tightly to the sideplate 24 and on the deck frame (not shown).

Although the foregoing description and accompanying drawings relate tospecific preferred embodiments of the present invention as presentlycontemplated by the inventor, it will be understood that variouschanges, modifications and adaptations, may be made without departingfrom the principles of the invention.

What is claimed is:
 1. A side tensioning assembly for retaining screenmedia to a side plate in a vibrating-type screening machine, the sideplate having an inner surface and an outer surface, the side tensioningassembly comprising: a tensioning rail mountable to the inner surface ofthe side plate and connectable to a portion of the screen media; atleast one angle box mountable to the outer surface of the side plate;and at least one bolt assembly for fastening the tensioning rail to theside plate and to the at least one angle box; the at least one boltassembly including a bolt connectable to the tensioning rail, the sideplate and the at least one of angle box, a nut threadably engaged withthe bolt for retaining the bolt to the at least one the angle box, and ashoulder bolt secured to a terminal end of the bolt; the shoulder boltbeing sized to prevent the nut from becoming physically separated fromthe bolt; the at least one angle box including an aperture definedtherein sized to allow the bolt assembly unobstructed passagetherethrough, and a movable plate with a cutout formed therein; thecutout being sized larger than the bolt but smaller than the nut; themovable plate being movable between a bolt-securing position and abolt-releasing position; in the bolt-securing position, the movableplate partially occluding the aperture in the angle box with the cutoutaligned with the aperture in the angle box such that when the bolt istightly fastened to the angle box with the nut, the tensioning rail isdrawn tightly against the inner surface of the side plate therebyapplying a tensile force to the portion of the screen media; in thebolt-releasing position, the movable plate being positioned so as toprovide unobstructed access to the aperture in the angle box such thatthe bolt assembly can be detached from the angle box without requiringdisassembly of the bolt assembly.
 2. The side tensioning assembly ofclaim 1 wherein the bolt is a carriage bolt.
 3. The side tensioningassembly of claim 1 wherein the nut is a flange nut.
 4. The sidetensioning assembly of claim 1 wherein: the nut is a first nut; and theside tensioning assembly further includes a second nut for securing thebolt to the tensioning rail.
 5. The side tensioning assembly of claim 4wherein the second nut is a half nut.
 6. The side tensioning assembly ofclaim 1 wherein the aperture in the angle box is circular.
 7. The sidetensioning assembly of claim 1 wherein the aperture in the angle box hasa shape selected from the group consisting of: (a) circle; (b) a square;(c) a rectangle; (d) an oval; and (e) an oblong.
 8. The side tensioningassembly of claim 1 wherein movement of the movable plate relative tothe angle box is selected from the group consisting of: (a) translation;(b) rotation; and (c) a combination of sliding and rotation.
 9. The sidetensioning assembly of claim 1 wherein the movable plate is slidablerelative to the angle box in a motion selected from the group consistingof: (a) side-to-side motion; (b) up and down motion and (c) motion alonga diagonal direction.
 10. The side tensioning assembly of claim 1wherein the movable plate is hingedly connected to the angle box. 11.The side tensioning assembly of claim 1 wherein the movable plate ispivotally connected to the angle box.
 12. The side tensioning assemblyof claim 1 wherein the movable plate is tethered to the angle box. 13.The side tensioning assembly of claim 1 wherein: the angle box includesfirst and second pins attached thereto; and the movable plate hasdefined therein first and second, spaced apart slots, each slot beingconfigured to receive therethrough a respective one of the first andsecond pins; the slots serving as a track to guide sliding movement ofthe movable plate relative to the angle box.
 14. The side tensioningassembly of claim 13 wherein the slots have an orientation selected fromthe group consisting of: (a) a vertical orientation; (b) a horizontalorientation; and (c) a diagonal orientation.
 15. The side tensioningassembly of claim 13 wherein the movable plate is generally planar andthe sliding movement of the movable plate is confined along the plane ofthe movable plate.
 16. The side tensioning assembly of claim 13 wherein:the angle box includes a base portion and a wedge-shaped structurecarried on the base portion; the wedge-shaped structure has an walloriented on an angle through which the aperture in the angle box isformed; and the movement of the movable plate between the bolt-releasingposition and the bolt-securing position occurs generally parallel to theangled wall of the wedge-shaped structure.
 17. The side tensioningassembly of claim 13 wherein: the angle box includes a base portion anda wedge-shaped structure carried on the base portion; the first andsecond pins being attached to one of the base portion and thewedge-shaped structure.
 18. The side tensioning assembly of claim 13wherein: the movable plate includes a first main planar portion and asecond portion angled away from the first main portion; and the firstand second slots extend through both the first and second portions ofthe movable plate.
 19. The side tensioning assembly of claim 16 wherein:the angle box includes a base portion and a wedge-shaped structurecarried on the base portion; the wedge-shaped structure has an walloriented on an angle through which the aperture in the angle box isformed; and when the movable plate is moved to its bolt-securingposition, the first main planar portion lies generally parallel to theangled wall of the wedge-shaped structure; and when the movable plate ismoved to its bolt-releasing position, the first main planar portion hasa skewed orientation relative to the angled wall of the wedge-shapedstructure.
 20. The side tensioning assembly of claim 1 wherein: theangle box includes a pin attached thereto; and the movable plate hasdefined therein a slot configured to receive therethrough the pin; theslot serving as a track to guide the sliding and the swiveling movementof the movable plate relative to the angle box.
 21. A side tensioningsystem for retaining screen media between opposed first and second sideplates in a vibrating-type screening machine, each side plate having aninner surface and an outer surface, the side tensioning systemcomprising: a first tensioning assembly operatively connectable to thefirst side plate; the first tensioning assembly including a firsttensioning rail mountable to the inner surface of the first side plateand connectable to a first portion of the screen media, at least oneangle box mountable to the outer surface of the first side plate, and atleast one bolt assembly for fastening the first tensioning rail to thefirst side plate and to the at least one angle box of the firsttensioning assembly; and a second tensioning assembly operativelyconnectable to the second side plate; the second tensioning assemblyincluding a second tensioning rail mountable to the inner surface of thesecond side plate and connectable to a second portion of the screenmedia, at least one angle box mountable to the outer surface of thesecond side plate, at least one bolt assembly for fastening the secondtensioning rail to the second side plate and to the at least one anglebox of the second tensioning assembly; and each bolt assembly includinga bolt connectable to one of the first and second tensioning rails, oneof the first and second side plates and one of the angle boxes, a nutthreadably engaged with the bolt for retaining the bolt to one of theangle boxes, and a shoulder bolt secured to a terminal end of the bolt;the shoulder bolt being sized to prevent the nut from becomingphysically separated from the bolt; each angle box including an aperturedefined therein sized to allow the bolt assembly unobstructed passagetherethrough, and a movable plate with a cutout formed therein; thecutout being sized larger than the bolt but smaller than the nut; themovable plate being movable between a bolt-securing position and abolt-releasing position; in the bolt-securing position, the movableplate partially occluding the aperture in the angle box with the cutoutaligned with the aperture in the angle box such that when one bolt ofthe bolt assembly is tightly fastened to the angle box with one nut ofthe bolt assembly, one of the first and second tensioning rails is drawntightly against the inner surface of one of the first and second sideplates thereby applying a tensile force to one of the first or secondportions of the screen media; in the bolt-releasing position, themovable plate being positioned so as to provide unobstructed access tothe aperture in the angle box such that the bolt assembly can bedetached from the angle box without requiring disassembly of the boltassembly.
 22. A vibrating-type machine comprising: a frame including adeck frame for supporting screen media; a pair of spaced apart first andsecond side plates attached to the frame; each side plate having aninner surface and an outer surface, a mechanism for imparting vibratorymovement to the frame; screen media positionable between the first andsecond side plates; a tensioning system for retaining screen mediabetween the first and second side plates, the side tensioning systemhaving: a first tensioning assembly operatively connectable to the firstside plate; the first tensioning assembly including a first tensioningrail mountable to the inner surface of the first side plate andconnectable to a first portion of the screen media, at least one anglebox mountable to the outer surface of the first side plate, and at leastone bolt assembly for fastening the first tensioning rail to the firstside plate and to the at least one angle box of the first tensioningassembly; and a second tensioning assembly operatively connectable tothe second side plate; the second tensioning assembly including a secondtensioning rail mountable to the inner surface of the second side plateand connectable to a second portion of the screen media, at least oneangle box mountable to the outer surface of the second side plate, atleast one bolt assembly for fastening the second tensioning rail to thesecond side plate and to the at least one angle box of the secondtensioning assembly; and each bolt assembly including a bolt connectableto one of the first and second tensioning rails, one of the first andsecond side plates and one of the angle boxes, a nut threadably engagedwith the bolt for retaining the bolt to one of the angle boxes, and ashoulder bolt secured to a terminal end of the bolt; the shoulder boltbeing sized to prevent the nut from becoming physically separated fromthe bolt; each angle box including an aperture defined therein sized toallow the bolt assembly unobstructed passage therethrough, and a movableplate with a cutout formed therein; the cutout being sized larger thanthe bolt but smaller than the nut; the movable plate being movablebetween a bolt-securing position and a bolt-releasing position; in thebolt-securing position, the movable plate partially occluding theaperture in the angle box with the cutout aligned with the aperture inthe angle box such that when one bolt of the bolt assembly is tightlyfastened to the angle box with one nut of the bolt assembly, one of thefirst and second tensioning rails is drawn tightly against the innersurface of one of the first and second side plates thereby applying atensile force to one of the first or second portions of the screenmedia; in the bolt-releasing position, the movable plate beingpositioned so as to provide unobstructed access to the aperture in theangle box such that the bolt assembly can be detached from the angle boxwithout requiring disassembly of the bolt assembly.
 23. A sidetensioning assembly for retaining screen media to a side plate in avibrating-type screening machine, the side plate having an aperture, aninner surface and an outer surface, the side tensioning assemblycomprising: a tensioning rail mountable to the inner surface of the sideplate and connectable to a portion of the screen media; at least oneangle box connected to the outer surface of the side plate; and at leastone bolt assembly for fastening the tensioning rail to the side plateand to the at least one angle box; the at least one bolt assemblyincluding a bolt connectable to the tensioning rail, the side plate andthe at least one of angle box, a nut threadably engaged with the boltfor retaining the bolt to the at least one the angle box, and a shoulderbolt secured to a terminal end of the bolt; the shoulder bolt beingsized to prevent the nut from becoming physically separated from thebolt; the at least one angle box including a cutout formed therein sizedlarger than the bolt but smaller than the nut; the angle box beingmovable relative to the side plate between a bolt-securing position anda bolt-releasing position; in the bolt-securing position, the angle boxpartially occluding the aperture in the side plate with the cutoutaligned with the aperture in the side plate such that when the bolt istightly fastened to the angle box with the nut, the tensioning rail isdrawn tightly against the inner surface of the side plate therebyapplying a tensile force to the portion of the screen media; in thebolt-releasing position, the angle box being positioned so as to provideunobstructed access to the aperture in the side plate such that the boltassembly can be detached from the side plate without requiringdisassembly of the bolt assembly.